Hybrid Multi-Infeed Interaction Factor Calculation Method Considering Voltage Regulation Control Characteristics of Voltage Source Converter

Voltage source converter based high voltage direct current(VSC-HVDC)can participate in voltage regulation by flexible control to help maintain the voltage stability of the power grid.In order to quantitatively evaluate its influence on the voltage interaction between VSC-HVDC and line commutated converter based high voltage direct current(LCC-HVDC),this paper proposes a hybrid multi-infeed interaction factor(HMIIF)calculation method considering the voltage regulation control characteristics of VSC-HVDC.Firstly,for a hybrid multi-infeed high voltage direct current system,an additional equivalent operating admittance matrix is constructed to characterize HVDC equipment characteristics under small disturbance.Secondly,based on the characteristic curve between the reactive power and the voltage of a certain VSC-HVDC project,the additional equivalent operating admittance of VSC-HVDC is derived.The additional equivalent operating admittance matrix calculation method is proposed.Thirdly,the equivalent bus impedance matrix is obtained by modifying the alternating current(AC)system admittance matrix with the additional equivalent operating admittance matrix.On this basis,the HMIIF calculation method based on the equivalent bus impedance ratio is proposed.Finally,the effectiveness of the proposed method is verified in a hybrid dual-infeed high voltage direct current system constructed in Power Systems Computer Aided Design(PSCAD),and the influence of voltage regulation control on HMIIF is analyzed.

Application of a Current and Voltage Mixed Control Mode for the New Fast Control Power Supply at EAST

A feedback control system is needed to restrain plasma vertical displacement in EAST （Experimental Advanced Superconducting Toknmak）. A fast control power supply excites active feedback coils, which produces a magnetic field to control the plasma＇s displacement. With the development of EAST, new demands on the new fast control power supply have led to an enhanced ability of fast response and output current, as well as a new control mode. The structure of cascaded and paralleled H-bridges can meet the demand of extended capacity, and digital control can reMize current and voltage mixed control mode. The validity of the proposed scheme is confirmed by experiments.

A Sliding Mode Approach to Enhance the Power Quality of Wind Turbines Under Unbalanced Voltage Conditions

An integral terminal sliding mode-based control design is proposed in this paper to enhance the power quality of wind turbines under unbalanced voltage conditions. The design combines the robustness, fast response, and high quality transient characteristics of the integral terminal sliding mode control with the estimation properties of disturbance observers. The controller gains were auto-tuned using a fuzzy logic approach.The effectiveness of the proposed design was assessed under deep voltage sag conditions and parameter variations. Its dynamic response was also compared to that of a standard SMC approach.The performance analysis and simulation results confirmed the ability of the proposed approach to maintain the active power,currents, DC-link voltage and electromagnetic torque within their acceptable ranges even under the most severe unbalanced voltage conditions. It was also shown to be robust to uncertainties and parameter variations, while effectively mitigating chattering in comparison with the standard SMC.

Voltage Mode Universal Filter Using Current Differencing Buffered Amplifier as an Active Device

Integrated filter circuit design resulted in desire for replacement of Inductors by active elements like Operational Amplifiers which led to the introduction of active filters. Active filter design has evolved over a period of time. Starting with OP AMPs, we have witnessed phenomenal growth of active component usage in filter design and development catering to varying requirements. This has contributed greatly in emergence of circuits with minimal limitations and advantages in terms of wide Bandwidth and High slew rates. Current Differencing Buffered Amplifier (CDBA) based active filter design has resulted in introduction of many novel circuits .This paper proposes a new Voltage-mode three input and Single output (TISO) multifunction filter based on single CDBA, four resistors and two capacitors. This second order filter circuit is capable of realizing various filter functions by choosing values of the three inputs variably. The natural frequency (ω0) can be tuned with passive components and the Q of the circuit is independent of (ω0) .The higher cascading capability of the circuit is ensured because of its low - output impedance. Further PSPICE-simulated results are in conformity with theoretical values.

MISO-Type Voltage-Mode Universal Biquadratic Filter Using Single Universal Voltage Conveyor

A universal biquadratic filter using single universal voltage conveyor (UVC), two resistors and two capacitors is presented in this paper. The proposed structure has three inputs and one output and can realize all the five standard biquadratic filters: low-pass (LP), high-pass (HP), band-pass (BP), band-reject (BR) and all-pass (AP) from the same circuit configuration. The presented universal filter offers low active and passive sensitivities. SPICE (Version 16.5) simulation results using 0.18 μm TSMC technology have been included.

DESIGN OF LOW-VOLTAGE AND LOW-POWER FULLY INTEGRATED FILTER BASED ON LOG-DOMAIN CURRENT-MODE INTEGRATOR

In this paper a novel log-domain current-mode integrator based on MOS transistors in subthreshold is proposed. The integrator's time-constant is tunable by varying a reference bias current. By use of the integrator, a fifth-order Chebyshev lowpass filter with 0.1dB ripples is designed. The simulation results demonstrate that the proposed filter has such advantages as low power supply(1.5V), very low power dissipation (μW level), nearly ideal frequency response, very small sensitivity to components in passband, and adjustable cut-off frequency over a wide range.The circuit is composed of NMOS transistors and grounded capacitors which make it suitable for fully integrated circuit implementation.

Voltage-Mode Universal Biquad Filter Employing Single Voltage Differencing Differential Input Buffered Amplifier

A new multi function voltage-mode universal biquadratic filter using single Voltage Differencing Differential Input Buffered Amplifier (VD-DIBA), two capacitors and one resistor is proposed. The proposed configuration has four inputs and one output and can realize all the five standard filters from the same circuit configuration. The presented biquad filter offers low active and passive sensitivities. The validity of proposed universal biquadratic filter has been verified by SPICE simulation using 0.35 μm MIETEC technology.

VDTA Based Electronically Tunable Voltage-Mode and Trans-Admittance Biquad Filter

In this paper, a biquad filter configuration based on two voltage differencing transconductance amplifiers (VDTAs) as newly active elements and only two capacitors as passive elements is proposed which can realize voltage-mode low pass (LP), band pass (BP), high pass (HP), band reject (BR) and all pass (AP) filtering responses using three voltage inputs. Simultaneously, the same configuration can also be used to obtain LP, BP and HP filtering responses in transadmittance-mode. The proposed biquad is capable of providing electronic control of quality factor independent of pole frequency through single transconductance parameter (biasing current). It also offers the advantage of low active and passive sensitivity. To support the theoretical analysis, the PSPICE simulation of the proposed circuit is done using 0.18 μm CMOS technology from TSMC.

A New Voltage-Mode Universal Biquadratic Filter Using Single UVC

The paper presents a new universal biquadratic filter using single universal voltage conveyor (UVC), two resistors and two capacitors. The offered structure has three inputs and one output and can realise all the five basic biquadratic filters: high-pass (HP), low-pass (LP), band-reject (BR), band-pass (BP) and all-pass (AP) from the same circuit topology. The proposed universal filter also provides following advantageous features, not available simultaneously in any UVC based universal biquadratic filter so far: (i) low active and passive sensitivities, (ii) independent control of natural frequency (ω0) and bandwidth (BW) and (iii) no requirement of any component matching condition and inversion of input signal(s) (as needed in most of the earlier reported structures). The workability of proposed structure has been presented by SPICE (Version 16.5) simulation using 0.18 μm TSMC technology.

Sampled-data modeling and dynamical effect of output-capacitor time-constant for valley voltage-mode controlled buck-boost converter

By analyzing the output voltage ripple of a buck-boost converter with large equivalent series resistance（ESR） of output capacitor, one valley voltage-mode controller for buck-boost converter is proposed. Considering the fact that the increasing and decreasing slopes of the inductor current are assumed to be constant during each switching cycle, an especial sampleddata model of valley voltage-mode controlled buck-boost converter is established. Based on this model, the dynamical effect of an output-capacitor time-constant on the valley voltage-mode controlled buck-boost converter is revealed and analyzed via the bifurcation diagrams, the movements of eigenvalues, the Lyapunov exponent spectra, the boundary equations,and the operating-state regions. It is found that with gradual reduction of output-capacitor time-constant, the buck-boost converter in continuous conduction mode（CCM） shows the evolutive dynamic behavior from period-1 to period-2, period-4, period-8, chaos, and invalid state. The stability boundary and the invalidated boundary are derived theoretically by stability analysis, where the stable state of valley voltage-mode controlled buck-boost converter can enter into an unstable state, and the converter can shift from the operation region to a forbidden region. These results verified by time-domain waveforms and phase portraits of both simulation and experiment indicate that the sampled-data model is correct and the time constant of the output capacitor is a critical factor for valley voltage-mode controlled buck-boost converter, which has a significant effect on the dynamics as well as control stability.

Voltage/Current-Mode Multifunction Filters Using One Current Feedback Amplifier and Grounded Capacitors

One configuration for realizing voltage-mode multifunction filters and another configuration for realizing current-mode multifunction filters using current feedback amplifiers (CFAs) are presented. The proposed voltage-mode circuit exhibit simultaneously lowpass and bandpass filters. The proposed current-mode circuit exhibit simultaneously lowpass, bandpass and highpass filters. The proposed circuits offer the following features: no requirements for component matching conditions;low active and passive sensitivities;employing only grounded capacitors and the ability to obtain multifunction filters from the same circuit configuration.

Single VDVTA-Based Voltage-Mode Biquad Filter

In this paper, an application of voltage differencing voltage transconductance amplifier (VDVTA) in the realization of voltage-mode (VM) multi-input single output (MISO) type biquad is presented. The proposed topology uses one VDVTA as an active element, two capacitors and a grounded resistor. The configuration realizes low pass (LP), high pass (HP), band pass (BP) and notch (BR) filters without the requirement of any matching condition. The natural frequency (w0) and bandwidth (BW) are independently controllable. The proposed circuit offers low active and passive sensitivities of w0. The operation of the proposed circuit has been verified through SPICE simulation with TSMC CMOS 0.18 μm process parameters.

CMOS VDIBAs-Based Single-Resistance-Controlled Voltage-Mode Sinusoidal Oscillator

In this communication, a new single-resistance controlled sinusoidal oscillator (SRCO) has been presented. The presented SRCO uses two voltage differencing inverting buffered amplifiers (VDIBAs), one resistor and two capacitors in which one is grounded (GC) and the other one is floating (FC). The proposed structure offers the following advantageous features: 1) independent control of oscillation condition (OC) and oscillation frequency (OF);2) low passive and active sensitivities and 3) very good frequency stability. The non-ideal effects of the VDIBA on the proposed oscillator have also been investigated. The proposed SRCO has been tested for its robustness using Monte-Carlo simulations. The check of the validity of the presented SRCO has been established by SPICE simulations using 0.18 μm TSMC technology.

Digitally Programmable Voltage Mode Universal Filters—A Minimal Realization

Three voltage mode universal filter biquads using digitally programmable second generation current conveyor (CCII) are presented in this paper. Salient features of proposed filter configurations include realization of all the filter functions except allpass, independently programmable filter parameters, no component matching constraint and low sensitivity figure. Component count of proposed filter configurations is proved to be minimal for offering aforementioned set of features. Workability of proposed circuit is verified by including the SPICE simulations.

Nth Order Voltage Mode Active-C Filter Employing Current Controlled Current Conveyor

This paper proposes an nth order (where n = 2,3, ,n) voltage mode active-C filter using n number of current controlled current conveyors (CCCIIs) and n number of equal valued grounded capacitors. The proposed topology can implement both band pass and low pass responses without alteration of any components. The filters offer the following important features: use of minimum number of current controlled current conveyors (CCCIIs) and passive components, no matching constraint, use of all grounded capacitors and absence of external resistor suitable for integration, cut off frequency can easily be electronically adjusted using AMS 0.35 μm CMOS technology. PSPICE simulation results of third order band pass and low pass responses are provided. The results are found to agree well with the theory.

Dual DVCC Based Voltage-Mode Digitally Programmable Biquadratic Filter

The recent advances in IC technology have led to the trend of designing hybrid systems to benefit both analog and the digital domain. Among analog circuits, multifunctional filter along with multiphase oscillator constitutes a building block of critical importance. In this paper, a digitally reconfigurable multi-input-multi-output voltage mode multifunctional biquadratic filter has been presented. The circuit comprises of two differential voltage current conveyors (DVCCs), two grounded capacitors and two floating resistors. The digital controllability is incorporated using a current-summing network (CSN). Tunability of quality factor is achieved by the use of a 3-bit digital control word while keeping the resonant frequency constant. PSPICE simulations using TSMC 0.25 μm CMOS technology have been performed to validate the theoretically predicted results.

Non-recessed-gate quasi-E-mode double heterojunction AlGaN/GaN high electron mobility transistor with high breakdown voltage

A non-recessed-gate quasi-E-mode double heterojunction A1GaN/GaN high electron mobility transistor （quasi-E- DHEMT） with a thin barrier, high breakdown voltage and good performance of drain induced barrier lowering （DIBL） was presented. Due to the metal organic chemical vapor deposition （MOCVD） grown 9-nm undoped A1GaN barrier, the effect that the gate metal depleted the two-dimensiomal electron gas （2DEG） was greatly impressed. Therefore, the density of carriers in the channel was nearly zero. Hence, the threshold voltage was above 0 V. Quasi-E-DHEMT with 4.1%tm source-to-drain distance, 2.6-μm gate-to-drain distance, and 0.5-μm gate length showed a drain current of 260 mA/mm. The threshold voltage of this device was 0.165 V when the drain voltage was 10 V and the DIBL was 5.26 mV/V. The quasi-E-DHEMT drain leakage current at a drain voltage of 146 V and a gate voltage of -6 V was below 1 mA/mm. This indicated that the hard breakdown voltage was more than 146 V.

Three-level inverter configuration with common mode voltage elimination for induction motor drive (To continue)

The multiplicity of vector combinations for vectors of combined three-level inverters plays an important role, when deciding on the modulation scheme, to obtain minimum switching per inverter vector change, as described in the next Section. This is not possible with reduced common-mode three-level inverter structure, obtained with a five-level cascaded H-bridge configuration, as the space vectors locations do not exhibit multiplicity. Moreover, the proposed configuration requires only two power supplies, whereas the scheme with the five-level H-bridge configuration requires six isolated power supplies.

New Voltage Mode Sinusoidal Oscillator Using Voltage Differencing Transconductance Amplifiers (VDTAs)

The purpose of this paper is to introduce a new electronically controlled voltage mode sinusoidal oscillator (VMSO) using Voltage Differencing Transconductance Amplifiers (VDTA). The proposed circuit provides electronic control of ω0 and independent condition of oscillation (CO). It is found that the oscillator works very satisfactorily and pure sinusoidal waveforms are available at the outputs. The PSPICE simulation confirms the theoretical results. The proposed oscillator circuit employs only two VDTAs, along with two grounded capacitor and single grounded resistor. The circuit exhibits low active and passive sensitivities for ω0. Simulation results are obtained by using PSPICE software with TSMC CMOS 0.18 um process parameters.